Fig 1: RIP1 promotes catabolism and inhibits anabolism in chondrocytes. (A) The mRNA levels of ECM-related biomarkers Mmp1, Mmp13, Il6, Acan, Col2a1, and Sox9 in rat chondrocytes treated with Ad-Ctl (100, 200 MOI) or Ad-Rip1 for 24 h (n = 5 for each group; three independent experiments). (B) The protein levels of MMP1, MMP13, IL6, COL2A1, SOX9, and RIP1 detected by western blotting assay in rat chondrocytes treated with Ad-Ctl (100, 200 MOI) or Ad-Rip1 for 24 h. (C,D) The concentration of GAG in cartilage explants (C) and the concentration of COMP released from the explants (D) treated with Ad-Ctl (100 MOI), Ad-Rip1 or Ad-Rip1 and Nec-1 (50 and 100 µM) for 10 days (n = 6 for each group). (E) Toluidine blue staining of the cartilage explants treated with Ad-Ctl (100 MOI), Ad-Rip1 or Ad-Rip1 and Nec-1 (100 µM) for 10 days (n = 6 for each group). (F) Alcian blue staining of the chondrocytes treated with Ad-Ctl (100 MOI), Ad-Rip1 or Ad-Rip1 and Nec-1 (100 µM) for 24 h (n = 6 for each group). *P < 0.05, **P < 0.01, and ***P < 0.001.